1. Field of the Invention
The present invention relates generally to a dispersing method, a dispersing apparatus and to a dispersing system having the dispersing apparatus and, more particularly, to a dispersing method, apparatus and system by which a material to be treated is finely ground and dispersed using a dispersing medium. The dispersing method, apparatus and system are characterized by supplying the material to be treated and the dispersing medium and by cleaning the dispersing apparatus after dispersion treatment.
2. Background Information
Medium-dispersing apparatuses of various types have been employed for the production of various products such as coating materials, printing ink, pigments and magnetic materials. In the foregoing medium-dispersing apparatuses, agitating motion is applied by an agitating means disposed in a dispersing chamber to a mixture of a dispersing medium and a material to be treated. The material to be treated is then finely ground by pulverization, shearing action and grinding action generated between the media to uniformly disperse the material in a liquid. If such an apparatus is designed so that adequate treatment time may be obtained for efficient dispersion, the dispersing chamber tends to be large and cannot be economically applied for the production of a small amount of product.
Further, the dispersing chamber in the foregoing medium-dispersing apparatuses is of a vertical-type or a horizontal-type, and a dedicated liquid-feeding pump is required to feed the material to be treated into the dispersing chamber. This is because when a non-dedicated liquid-feeding pump is used, if the dispersing medium flows out of the dispersing chamber and enters into the pump, the pump tends to jam, and if an outflow-preventing mechanism is provided to prevent outflow of the dispersing medium, such a mechanism is not completely cleaned after the dispersion treatment, thereby resulting in further problems when the apparatus is used to treat different materials.
Moreover, prior to the dispersion treatment, a predetermined amount of the dispersing medium is required to be charged uniformly into the dispersing chamber. However, this charging operation is troublesome, for example, depending on the structure of the dispersing apparatus, since the charging operation is necessarily required to be performed in several operations, resulting in a long charging time and sometimes in poor operability of the apparatus.
In the cleaning operation after completion of the dispersion treatment or at the time of changing the types of materials, the dispersing chamber and production lines have to be cleaned, and the dispersing medium has to be discharged from the dispersing chamber for cleaning. However, the operation for discharging the dispersing medium cannot be readily carried out. Further, solid or liquid stains adhere to corner portions of pipelines of the production line, whereby the cleaning operation is incomplete and a large amount of cleaning liquid is required. Accordingly, the types of products which can be treated by one medium-dispersing apparatus is fixed, and the range of application by one apparatus is restricted.
A dispersing apparatus has been known which utilizes a rotary disc-type dispersing device for dispersion-treating a small amount of a material to be treated without using the conventional dispersing chamber and pump, thereby eliminating jamming of the dispersing medium. (See Japanese Unexamined Patent Publication No. 7-116488). In this dispersing apparatus, the dispersing medium is first charged into a dispersing chamber. The material to be treated is then drawn in by suction from a tank into the dispersing chamber by rotation of a disc. A dispersion treatment is performed by rotating the disc to mix the dispersing medium and the material to be treated in the dispersing chamber. A filter is fixed to an inner circumferential surface of the dispersing chamber leading to a delivery port and allows the dispersed material but not the dispersing medium to pass therethrough. By this construction, only the dispersed material is permitted to flow from the dispersing chamber back to the tank through a pipeline connecting the delivery port of the dispersing chamber in fluid communication with the tank. During a cleaning operation, the dispersing medium is removed from the dispersing chamber.
However, problems similar to those of the foregoing conventional techniques have sometimes occurred with the dispersing apparatus disclosed in Japanese Unexamined Patent Publication No. 7-116488 with respect to the charging of the dispersing medium, the discharging during cleaning operations, or the cleaning of pipelines of the production line.